André Twele

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Losses of biodiversity and ecosystem functioning due to rainforest destruction and agricultural intensification are prime concerns for science and society alike. Potentially, ecosystems show nonlinear responses to land-use intensification that would open management options with limited ecological losses but satisfying economic gains. However,(More)
A two-component fully automated flood monitoring system is described and evaluated. This is a result of combining two individual flood services that are currently under development at DLR’s (German Aerospace Center) Center for Satellite based Crisis Information (ZKI) to rapidly support disaster management activities. A first-phase monitoring component of(More)
The tropical rain forests in Indonesia are affected by socio-economic and ecological factors and processes that result in an increasing destabilisation of the rainforest margins. Optical satellite data have been explored to document changes in land cover throughout the past 30 years and to monitor the current status and dynamics of land cover and land cover(More)
In this contribution, a hybrid multi-contextual Markov model for unsupervised near real-time flood detection in multi-temporal X-band synthetic aperture radar (SAR) data is presented. It incorporates scale-dependent, as well as spatio-temporal contextual information, into the classification scheme, by combining hierarchical marginal posterior mode (HMPM)(More)
Topographic correction is an important data preprocessing step when land cover classification and quantitative analysis of multispectral data are carried out in mountainous regions. Solar illumination effects may cause variations in reflectance of similar ground features, leading to a possible misclassification due to different topographic positions. Since(More)
Medium resolution SAR satellite data have been widely used for water and flood mapping in recent years. Since the beginning of 2008 high resolution radar data with up to one meter pixel spacing of the TerraSAR-X satellite are operationally available. The improved ground resolution of the system offers a high potential for water detection. However, image(More)
In a classical approach, optical data are being used for forest fire detection in a rush mode. Difficulties arise due to persistent cloud coverage, haze layers and smoke plumes. In contrast, radar measurements offer high acquisition rates because of their ability to penetrate clouds and their independence of sun illumination. However, a visual(More)